PURE EVIL: Horrific security video shows the deadly sequence yesterday of a madman spraying his elderly victim in an elevator with accelerant, and about to set her alight.AP

The elderly Brooklyn woman burned to death by a madman in her apartment-building elevator was described today as a “wonderful” person who always looked out for her neighbors and community.

“Everybody in the neighborhood would tell you, anything she had in her house she’d give you,” said Dorinda Thomas, 56, adding that tragic victim Dolores Gillespie was her nephew’s grandmother. “She was a wonderful lady, you understand.”

Thomas said Gillespie was “desperately afraid” of the perp, but didn’t know why he was staying in her apartment. She claimed Gillespie – who had a son named Maurice as well as a daughter – had complained to the cops about her killer, a 47-year-old who is in custody but has not been identified.

Gillespsie was horrifically killed Saturday when the maniac sprayed her with flammable liquid and set her alight with a Molotov cocktail, cops said.

Margie Grooms, 67, who lives on the block, said Gillespie was a “community activist” who was affiliated with the local precinct.

“She did a lot community work. I think she was a great person. I didn’t know him at all,” she said, referring to the monster, whose vicious attack was caught on surveillance video.

Another neighbor who would only say her name was Rose, said Gillespie “was a lady who looked out for everybody. Whoever did this had no heart.”

Today, a memorial candle was lit on stoop of the Prospect Heights building.

The floor by now-out-of-service elevator where she was killed was polluted with water, muddy ash and a pile of burned out debris.

Other neighbors described a harrowing scene.

“She was screaming at the top of her lungs,” said a resident of the building who heard the sounds of the struggle at around 4:15 p.m.

Dolores Gillespie, 64, was returning from grocery shopping when the elevator stopped on the fifth floor of the building at 203 Underhill Ave.

Her killer — who is believed to be a current or former boyfriend — was waiting in the hallway to strike.

He was holding two terrifying murder weapons — an exterminator-style spray can filled with flammable liquid and a bottle gas-bomb.

Before Gillespie could even step out of the elevator, the fiend, wearing a dust mask atop his head, doused her with the accelerant.

The liquid’s container had a hose like those commonly found on insecticide cannisters, NYPD spokesman Paul Browne said.

“He opens the door and sprayed her methodically over her head, over her body,” Browne said.

“She’s cowering, trying to protect her face with her hands.”

The 47-year-old, dressed all in black except for white gloves and the white mask atop his head, stepped out of the elevator and lit the explosive, Browne said.

The killer opened the elevator door again and threw the Molotov onto Gillespie, setting her on fire, Browne said.

But the vicious sicko wasn’t done. He opened the elevator door a final time to spray more accelerant on the burning woman before fleeing, Browne said.

Police sources described the attack as a domestic incident, and Brown confirmed the pair knew each other.

Gillespie’s neighbors were stunned by the hideous crime.

“This is devastating,” said Heidi Matthews, who has known the victim for decades, and said the woman worked for the Post Office.

“She was a fixture in the neighborhood for years. This is unreal. There was nothing she wouldn’t do for you. She bought me flowers for Mothers’ Day.

“She would come home from shopping and say, ‘I have some extra of this, do you need anything?,’ ” said Matthews, 46.

Neighbor Chris Martinez said “she didn’t have any enemies.”

Another neighbor, who heard the victim’s blood-curdling screams, said he rushed out of his apartment to look for the woman.

“I smelled smoke, and then ran back upstairs to call 911,” said the man, who gave his name as David.

“It sounded like a person being attacked, rather than someone stuck in an elevator,” said the neighbor. “It sounded like she was in trouble.”

The fire was raging in the building when residents realized the danger.

“It was a completely glowing flame,” said another tenant, who didn’t want his name revealed.